As shown in FIG. 1 and FIG. 2, the structure of the conventional coaxial cable feeder connector comprises a printed insulating base plate 2, soldered to the upper edge of the connector body 1, and a top part 9 of the contact point spring leaf protruding from the hollow part of the connector body 1. The structure further includes a converter consisting of three capacitors 4, one transformer 5, a twin lead feeder terminal 7 and contact point 6, soldered to the base plate 2 so that the coaxial cable feeder can be converted to a twin lead type cable feeder. Two sets of protruding ends 3 are formed on the connector body 1 to serve as a socket for receiving the two-pin part 10 of the base plate 2, and one of the pins is soldered to the set of protruding ends. A safety sleeve 8 is fitted over the feed connector to protect it from being damaged. In this prior art of structure, because the two-pin part 10 of the base plate 2 is fastened only by means of two sets of protruding ends 3, and since only one of the pins is to be soldered to a set of protruding ends, it is not solid enough and it is easy to shake, especially when the connected feeder is tripped or treaded by someone, and the base plate 2 will be shaken violently, and the pin pulled with the feeder may be broken or may fall off. The result is an open circuit, which requires frequent repairing, soldering or replacement. This is very troublesome.
To eliminate the above mentioned disadvantages, the inventor has studied and improved the feeder connector and completed the invention as shown in FIG. 3 and FIG. 4. This invention relates a printed insulating base plate 12, having two notches at two sides of its lower end, and having a metallic coating applied in the vicinity of the two notches for soldering purpose. On the upper edge of the connector body 11, two shaped protruding pieces 13 are formed to serve as slots for the end of the base plate 12 which has two notches 18, so that the base plate 12 will not shake. The top part 19 of the contact point spring leaf of the connector body 11 is in contact with the center of the lower end of the base plate 12, and is soldered with a tin solder.
The former of the above mentioned two types is conventional and the latter is the one which has previously been improved by the inventor. However, the two types use a similar printed insulating base plate for the purpose of avoiding the influence of magnetic flux on the transformers 5 and 15 causing lower efficiency in receiving signals, if metallic base plate is used. In fact, according to the result of the experiments conducted in recent years and the experience obtained during practical usage by the inventor, the above mentioned point of view still has to be corrected. The reason why the efficiency in receiving signals will be lowered is due to the error of fixing positions of the elements including transformers 5 and 15 and capacitors 4, 14 as well as due to the error of the fixing method, not due to the material of the base plate. When the conventional printed base plate is used, it is necessary to first drill holes in the base plate. The elements are arranged according to their respective positions, and then are soldered in position. The soldering operation is time-consuming and exhausting work. In case of even the slightest deviation from the right position on the part of the operator, it is possible to make a positioning error, which affects the receiving efficiency. For this reason, the above mentioned two types of feeder connector cannot meet the strict requirements. Furthermore, when the printed insulating base plate is used, the place to be soldered should be first coated with a metallic coating to serve as the base layer for soldering. This will increase the processing procedure and eventually its cost. Since most of such small parts are manufactured in mass production, the slightest increase in unit cost will make a significant difference in total cost.
Not long ago, the inventor studied, designed and improved again, and a patent application was filed on Mar. 12, 1982 in the U.S. Patent Office with the application Ser. No. 357,797. The structure set forth in this patent application is shown in FIG. 5, FIGS. 6A, 6B, 6C and FIG. 7, in which the metallic base plate 20, having a clip-like opening formed by upper and lower clip-leafs 21, 22 are situated at a specific position on the metallic base plate 20 to fix the transformer 25. The clip leafs 21 and 22 are made by punch molding. In addition, two protrusion holes 23 and 24, formed on the sides of the base plate 20, can be used to hold the capacitors 26 to correctly position them. The top part of the base plate 20 is also formed with a protruding rod 27 during the same punching operation. This rod 27 can be directly inserted into the perforated hole 28, and then by means of pressing, the end of the rod 27 can be made flush with the feeder in order to fix the position for the two ends 29. The bottom part of the base plate 20 is made into a loop 37. After the contact point spring leaf 36 is put into the hole 35 in the body 30, the two protruding rods 38 and 39 within the loop 37 can mesh with two flanges 31 and 32 on the top surface of the body 30, and can be put into the two notches 33 and 34 between the two flanges 31 and 32. By means of the pressing operation the body of the flanges 31 and 32 near the two notches can be lowered so that two protruding rods 38 and 39 of the loop 37 of the base plate 20 will be firmly squeezed in the notches, and the contact point spring leaf body 36 can also be fixed in the hole 35.
From what has been described above, it shows that although the U.S. patent application Ser. No. 357,797 has overcome some problems of the conventional and improved feeder connectors, and thus is capable of reducing the time-consuming procedure of soldering, saving the time required for processing and avoiding the consideration of the possibility of damaging the connection between the base plate element and connector body, as a matter of fact, the patent application Ser. No. 357,797 still has some disadvantages. Specifically, the processing procedure has not been simplified to the utmost, and the manufacturing cost is still not minimized. This causes slow processing and extra expenses. These are the difficulties which cannot be overcome.